ESPN 51th Annual Meeting

ESPN 2018


 
Antimicrobial activity of peritoneal fluid in children on peritoneal dialysis
VALYA GEORGIEVA 1 WITCHUDA KAMOLVIT 2 PETRA LÜTHJE 2 RUKSHANA SHROFF 3 ANNELIE BRAUNER 2 MILAN CHROMEK 1

1- DIVISION OF PEDIATRICS, DEPARTMENT OF CLINICAL SCIENCE, INTERVENTION AND TECHNOLOGY, KAROLINSKA INSTITUTET AND KAROLINSKA UNIVERSITY HOSPITAL, STOCKHOLM, SWEDEN
2- DIVISION OF CLINICAL MICROBIOLOGY, DEPARTMENT OF MICROBIOLOGY, TUMOR AND CELL BIOLOGY, KAROLINSKA INSTITUTET AND KAROLINSKA UNIVERSITY HOSPITAL, STOCKHOLM, SWEDEN
3- GREAT ORMOND STREET HOSPITAL FOR CHILDREN NHS FOUNDATION TRUST, LONDON, UK
 
Introduction:

 Peritonitis is the commonest risk associated with peritoneal dialysis (PD). Interestingly, some patients appear to be resistant to peritonitis while others suffer from recurrent infections that often lead to catheter removal and loss of peritoneal membrane function. The aim of our study is to characterize endogenous antimicrobial components in the PD fluid to better understand innate immunity of the peritoneal cavity.

Material and methods:

 We collected peritoneal fluid from 5 children on PD with no infections in the preceding 6 weeks and with no antibiotic treatment. Two samples were collected from each patient: 1. fluid that had been in the peritoneal cavity for 12 hours, and 2. fluid that had been in the peritoneal cavity for 1 hour. The samples were centrifuged, supernatants were desalted and concentrated 500 times. An antimicrobial assay with the 2 commonest organisms causing peritonitis, Staphylococcus epidermidis and Escherichia coli, embedded in agarose, was used. Known antimicrobial peptides were measured in the fluid by enzyme-linked immunosorbent assay.

 

Results:

All PD samples showed significant antimicrobial activity against both tested bacteria. PD fluid that had been in the peritoneal cavity for 12 hours, displayed stronger antimicrobial activity compared with 1-hr samples. Known antimicrobial peptides cathelicidin (LL-37) and human β-defensin-2 (hBD-2) were measurable in all 12-hr samples, with significantly lower or negative levels in 1-hr samples. However, the detected concentrations of LL-37 and hBD-2 were too low to explain the results observed in the antimicrobial assay.

Conclusions:

 There is a significant antimicrobial activity against both gram-negative and gram-positive bacteria secreted into PD fluid in uninfected children. PD fluid is positive for antimicrobial peptides LL-37 and hBD-2 but our results suggest the presence of additional antimicrobial substances. We are planning further systematic studies to identify all antimicrobial components the peritoneal fluid and correlating this with the patients clinical and biochemical status.